SE305011B - - Google Patents

Abstract

978,862. Multiple channel transmission systems. SIEMENS-HALSKE A.G. April 25, 1962 [April 28, 1961], No. 15702/62. Heading H4L. In an arrangement in which a number of high frequency channels are transmitted over a common aerial system, the channels are combined at the transmit station and distributed at the receiver station in a manner which minimizes the differences in transit time between channels and this difference is further minimized by connecting a delay distortion correcting device in each transmit and/or receive channel. The arrangement, Fig. 2 for a four-channel system comprising four transmitters connected to terminals a-d and four receivers connected to terminals a<SP>1</SP> to d<SP>1</SP>, includes a common aerial system A and a transmit and receive distributer WI and WII, respectively. Each distributer includes four filters, one associated with each channel which pass signals in that channel with little energy loss and acts as a low loss reflector to the signals in the other channels and two circulators, e.g. RG1, RG2, around which the signals are channelled in the direction of the arrow. The difference in transit time between channels is minimized by connecting the transmitters and receivers to terminals a-d and a<SP>1</SP>-d<SP>1</SP> in such a manner, e.g. Fig. 3, that the signals in each channel are subjected to three filter reflections in passing from a transmitter to its associated receiver. Considering transmitter 2, its signal is applied to terminal c, is passed by filter Fc, is transferred from circulator RG2 to RG1, is reflected by filters Fb and Fa, is transmitted via line L1, the aerial system and line LII to receiver circulator RG<SP>1</SP>, is reflected by filter Fa<SP>1</SP> and passed via filter Fb<SP>1</SP> to receiver 2. The delay distortion correcting device, Fig. 9, which is connected in each channel, comprises two wave guide sections H 1 , H 2 disposed parallel to each other and coupled via aperture L to form a 3db directional coupler and extended to form two tunable cavities forming parallel resonant circuits which are tuned to the appropriate channel frequency by a common control.